SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57c151713cb3a8df066e785807ff525bcc7ca6e6b5c34c57b0aa57a538b14aa9' 
  AND token = 'AWXqn5YhojuOPosQANaDPjEMh5uCZQmsRtSzWni9N4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}